Pipe coupling

ABSTRACT

A pipe coupling includes a body member ( 10 ) formed with a bore ( 11 ) for receiving one end of a pipe (P) to be coupled; a sealing ring ( 20 ) and a compression sleeve ( 30 ) receivable within the bore ( 11 ); a radially-deformable gripping ring ( 40 ) having one end abuttable against the compression sleeve ( 30 ), a securing nut ( 50 ) threaded on the body member ( 10 ) and engageable with the gripping ring ( 40 ) to move the gripping ring ( 40 ) axially and to effect a sealing action via the compression sleeve ( 30 ) and the sealing ring ( 20 ), and also to compress the gripping ring ( 40 ) radially to effect a gripping action of the pipe (P) received in the bore ( 11 ); and an axially-extending limit element ( 45 ) between the gripping ring ( 40 ) and the body member ( 10 ) effective to cause the nut ( 50 ), when tightened; (a) in an initial stage, to move the gripping ring ( 40 ) and the compression sleeve ( 30 ) until the limit element engages ( 45 ) prevents further axial movement of the gripping ring ( 40 ); and (b) in a final stage, to radially deform the gripping ring ( 40 ) to produce the gripping action, and then to compress the sealing ring ( 20 ) against the internal annular shoulder ( 14 ) of the body member to produce the sealing action.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to pipe couplings, and particularly to pipe couplings of the compression type, such as are described, for example in U.S. Pat. Nos. 4,025,093 and 4,083,587, assigned to the assignee of the present application.

Pipe couplings of this type generally comprise: a body member formed with a bore for receiving one end of a pipe to be coupled, an annular shoulder to enclose the pipe when received in the bore, and threads for threadedly receiving a securing nut; a sealing ring receivable within the bore and engageable with the annular shoulder for producing a sealing action with respect to the pipe when received in the bore; a compression sleeve also receivable within the bore and engageable with the sealing ring for compressing the sealing ring against the annular shoulder of the body member; a radially-deformable gripping ring having one end abuttable against the compression sleeve, and also having an inner surface producing a gripping action with respect to the pipe when the gripping ring is radially deformed; and a securing nut having threads mating with the threads on the body member and engageable with the gripping ring to move the gripping ring axially and to effect the sealing action via the compression sleeve and the sealing ring, and also to compress the gripping ring radially to effect the gripping action of the pipe received in the bore.

Pipe couplings of the foregoing type will hereinafter be referred to as “pipe couplings of the type herein described”.

Pipe couplings of the type herein described, which are presently in wide-spread use, normally require pushing the pipe through the seal (typically an O-ring) in the bore of the body member in order to achieve compression of the O-ring on the pipe, and thus a leak free joint. However, for pipes of large diameters, the operation of pushing the pipe through the O-ring seal requires a large force, making the operation very difficult, and sometimes even necessitating an extra operation of chamfering the pipe end for this purpose.

A further disadvantage in pipe couplings of the type herein described now in use is that such couplings do not tolerate substantial variations in the pipe diameter so that precise pipe diameter tolerances must be maintained, or a large number of differences in diameter sizes; improved sealing even or damaged pipes, particularly since the seal produces double sealing points; and convenient disassembly of the coupling, since relaxation of the sealing ring releases the pipe end for removal and also “springs” the compression sleeve, the split ring and the nut during disassembly.

Further features and advantages of the invention will be apparent from the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view illustrating one form of pipe coupling constructed in accordance with the present invention;

FIG. 2 is an enlarged sectional view illustrating the pipe coupling of FIG. 1 during the initial tightening stage of the securing nut;

FIG. 3 illustrates the pipe coupling of FIG. 1 in the final tightened state of the nut;

FIGS. 4, 5 and 6, are views corresponding to FIGS. 1, 2 and 3, respectively, illustrating another form of pipe coupling constructed in accordance with the present invention wherein the limit elements, in the form of a plurality of fingers, are integrally formed with the body member, rather than with the gripping ring;

FIG. 7 is a view similar to that of FIG. 4, but showing the fingers integrally formed on an abutment ring between the body member and the sealing ring;

FIG. 8 is a view similar to that of FIG. 7, but showing the abutment ring between the sealing ring and the compression sleeve; and

FIG. 9 is a view similar to that of FIG. 8, but showing the abutment ring between the gripping ring and the compression sleeve.

DESCRIPTION OF A PREFERRED EMBODIMENT

The Embodiment of FIGS. 1-3

The pipe coupling illustrated in FIGS. 1-3 is of the type herein described (as defined above) but modified to include the features of the present invention set forth above, and as to be described more particularly below. As shown in FIG. 1, such a pipe coupling includes the following basic parts: a body member 10; a sealing ring 20; addition, its outer surface is formed with a shallow annular rib 33 at the end of the sleeve facing body member 10. Rib 33 is cooperable with rib 15 of the body member to releasably hold the compression sleeve, and with it the resilient ring 20, during the assembling of the coupling.

The opposite end of the compression sleeve 30, i.e., the end facing the gripping ring 40, is formed with a radial flange 34 having a plurality (in this case three) axially-extending slots or recesses 35 spaced around its periphery, for reasons to be described below. The inner surface of flange 34 facing the gripping ring 40 is inwardly tapered in the direction of the gripping ring, as shown at 36 in FIGS. 2 and 3.

The gripping ring 40 is made of a hard, elastic plastic material, such as an acetal resin. It is formed with a slit 41 extending axially for the complete length of the ring to make it radially deformable. Its inner surface is formed with annular barbs or ribs 42 adapted to penetrate the outer surface of the pipe P when the ring is radially contracted. The outer surface of split ring 40 is formed with a plurality of axially-extending circumferentially-spaced ribs 43 of increasing height joined to an annular rib 44 at the end of the split ring 40 facing the compression sleeve 30.

The end of gripping ring 40 facing compression sleeve 30 is further formed with a plurality of axially-extending projections 45, serving as axially-extending limit elements between the gripping ring 4 and the body member 10. These limit elements 45 are in the form of fingers and are effective to assure that, during the tightening of the nut 50 as will be described below, first the sealing ring will be partly compressed to produce a seal, then the gripping ring will be compressed to firmly grip the pipe inserted into the body member, and finally the sealing ring will be more firmly compressed to assure a good seal, even when using a sealing ring of slightly larger diameter than the outer diameter of the pipe to facilitate insertion of the pipe.

There is one finger 45 of each of the recesses 35 formed in flange 34 of the compression sleeve 30. Each finger 45 includes an outwardly-extending shoulder 46 at its outer tip. The inner surface of each finger 45 is outwardly tapered in the direction of the compression sleeve 30, as shown particularly in FIGS. 2 and 3. The outer surfaces of the ribs 43 of gripping 40 are tapered, decreasing in height towards the nut 50. surface of pipe P. The radial deformation of gripping ring 40 produces a firm gripping action between it and the pipe.

Continued rotation of nut 50 moves the compression sleeve 30 axially of the pipe, by virtue of the engagement of shoulder 55 of the nut flange 34 of the compression sleeve, thereby moving the compression sleeve towards shoulder 14. This further compresses the sealing ring 20 against the annular shoulder 14 of body member 10, to produce a firm sealing action, as shown in FIG. 3.

For disassembling the pipe P, it is only necessary to rotate nut 50 in the loosening direction, permitting the pipe P to be pulled out of the coupling.

It will thus be seen that the illustrated coupling provides a number of important advantages. Since the sealing ring 20 in its relaxed condition can be made of larger diameter than the pipe P to be inserted, a pipe may be easily inserted into the coupling and through the seal. Also, since the pipe is more freely inserted through the sealing ring, there is better assurance that the end of the pipe P will be in its proper position, firmly abutting annular shoulder 12 of body member 10, before the final tightening of the nut 50 which effects the firm gripping of the pipe.

The illustrated coupling also produces an excellent seal since it provides two sealing points on the outer surface with respect to the body member, and a sealing surface of substantial area on its inner surface with respect to the pipe P. The described seal produces a substantial displacement of both its inner and outer sealing surfaces, allowing for a relatively large sealing stroke particularly when the middle rib 22 is also included, thereby enabling the seal to accommodate a wide variation of pipe diameters. In addition, when the stress is removed from the seal by loosening nut 52 to permit disassembly, the seal produces a “spring action” when returning to its original unstressed condition, pushing out the compression sleeve and split ring, thereby facilitating the disassembly of the coupling.

The assembly of the coupling is facilitated by the provision of the shallow annular ribs 15 and 33 on the body member 10 and compression sleeve 30, respectively, which releasably retain these parts together during the initial assembly and also during installation or repair in the field. so as to function in the same manner as described above with respect to FIG. 4-6 during the tightening of the nut.

FIG. 9 illustrates the variation wherein the abutment ring 160 is interposed between the gripping ring 40 and the compression sleeve 30, with its axially-extending limit elements, in the form of fingers 161, facing the body member 10. Thus, fingers 161 will function in the same manner as fingers 45 in the embodiment of FIGS. 1-3 during the tightening of the nut 50.

While the invention has been described with respect to several preferred embodiments, it will be appreciated that they are set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made. 

What is claimed is:
 1. A pipe coupling comprising: a body member formed with a bore for receiving one end of a pipe to be coupled, an internal annular shoulder to enclose the pipe when received in the bore, and threads for threadedly receiving a securing nut; a sealing ring receivable within said bore and engageable with said annular shoulder for producing a sealing action with respect to the pipe when received in the bore; a compression sleeve also receivable within said bore and engageable with said sealing ring for compressing said sealing ring against said annular shoulder of the body member; a radially-deformable gripping ring having one end abuttable against said compression sleeve, and also having an inner surface producing a gripping action with respect to the pipe when the gripping ring is radially deformed; and a securing nut having threads mating with the threads on the body member and engageable with said gripping ring to move the gripping ring axially and to effect said sealing action via the compression sleeve and the sealing ring, and also to compress the gripping ring radially to effect said gripping action of the pipe received in said bore; characterized in that said pipe coupling further comprises an axially-extending limit element between said gripping ring and said body member effective to cause the nut, when tightened: (a) in an initial stage, to move the gripping ring and the compression sleeve, and to start compressing the sealing ring, until said limit element prevents further axial movement of the gripping ring; and (b) in a final stage, to radially deform the gripping ring to produce said gripping action, and then to further compressing said sealing ring against said internal annular shoulder of the body member to produce said sealing action.
 2. The coupling according to claim 1, wherein said nut is formed with an internal annular shoulder engageable with the end of the compression sleeve facing the gripping ring, which annular shoulder engages said end of the compression sleeve to move the compression sleeve and the sealing ring axially in said final stage, compressing said sealing ring against said internal annular shoulder of the body member.
 3. The coupling according to claim 2, wherein: said compression sleeve is formed with a radical flange at the end thereof facing the gripping ring; said limit element includes a plurality of fingers spaced circumferentially around said abutting end of the gripping ring and extending axially towards the body member; and said radial flange on the compression sleeve is formed with a recess for accommodating each of said fingers of the gripping ring.
 4. The coupling according to claim 3, wherein said plurality of fingers are integrally formed on said gripping ring and are abuttable with said body member in said initial nut tightening stage (a).
 5. The coupling according to claim 3, wherein said plurality of fingers are integrally formed on said body member and are abuttable with said gripping ring in said initial nut tightening stage (a).
 6. The coupling according to claim 3, wherein said plurality of fingers are integrally formed on an abutment ring adjacent said body member and are abuttable with said gripping ring in said initial nut tightening stage (a).
 7. The coupling according to claim 3, wherein said plurality of fingers are integrally formed on an abutment ring adjacent said gripping ring and are abutable with said gripping ring in said initial nut tightening stage (a).
 8. The coupling according to claim 1, wherein said gripping ring is a split ring having an outer tapered surface cooperable with an inner tapered surface on the nut, and an inner barbed surface for gripping the pipe.
 9. The coupling according to claim 1, wherein said sealing ring is integrally formed on its outer surface with at least two annular ribs, one at each end.
 10. The coupling according to claim 9, wherein the end ribs of the sealing ring are of substantially semi-circular cross-section, and the sealing ring is also integrally formed with a middle rib of substantially triangular cross-section.
 11. The coupling according to claim 1, wherein the bore in the body member is formed with an annular rib at the end thereof opposite to that formed with said annular shoulder, and the end of the compression sleeve facing the sealing ring is formed with an external rib dimensioned to releasably retain the compression sleeve, and the sealing ring, within the body member bore during the preliminary assembly of the coupling.
 12. A pipe coupling comprising: a body member formed with a bore for receiving one end of a pipe to be coupled, an annular shoulder to enclose the pipe received in the bore, and threads for threadedly receiving a securing nut; a sealing ring receivable within said bore and engageable with said annular shoulder for producing a sealing action with respect to the pipe when received in the bore; a compression sleeve also receivable within said bore and engageable with said sealing ring for compressing said sealing ring against said annular shoulder of the body member; a radially-deformable gripping ring having one end abuttable against said compression sleeve, and also having an inner surface producing a gripping action with respect to the pipe when the gripping ring is radially deformed; and a securing nut having threads mating with the threads on the body member and engageable with said gripping ring to move the gripping ring axially and to effect said sealing action via the compression sleeve and the sealing ring, and also to compress the gripping ring radially to effect said gripping action of the pipe received in said bore; said sealing ring being integrally formed on its outer surface with at least two annular ribs, one at each end.
 13. The coupling according to claim 12, wherein the end ribs of the sealing ring are of substantially semi-circular cross-section, and the sealing ring is also integrally formed with a middle rib of substantially triangular cross-section.
 14. The coupling according to claim 12, wherein said pipe coupling further comprises an axially-extending limit element between said gripping ring and said body member effective to cause the nut, when tightened; (a) in an initial stage, to move the gripping ring and the compression sleeve, and to start compressing the sealing ring, until said limit element prevents further axial movement of the gripping ring, and (b) in a final stage, to radially deform the gripping ring to produce said gripping action, and then to further compressing said sealing ring against said internal annular shoulder of the body member to produce said sealing action.
 15. The coupling according to claim 14, wherein said nut is formed with an internal annular shoulder engageable with the end of the compression sleeve facing the gripping ring, which annular shoulder engages said end of the compression sleeve to move the compression sleeve and the sealing ring axially in said final stage, compressing said sealing ring against said internal annular shoulder of the body member.
 16. The coupling according to claim 15, wherein: said compression sleeve is formed with a radial flange at the end thereof facing the gripping ring; said limit element includes a plurality of fingers spaced circumferentially around said abutting end of the gripping ring and externally axially towards the body member; said radial flange on the compression sleeve formed with a recess for accommodating each of said fingers of the gripping ring; and in said initial (a), one end of the sealing ring is also moved axially to partially compress the sealing ring, which sealing ring is further compressed to produce said sealing action during said final stage (b).
 17. A pipe coupling comprising: a body member formed with a bore for receiving one end of a pipe to be coupled, an annular shoulder to enclose the pipe received in bore, and threads for threadedly receiving a securing nut; a sealing ring receivable within said bone and engageable with said annular shoulder for producing a sealing action with respect to the pipe when received in the bore; a compression sleeve also receivable within said bore and engageable with said sealing ring for compressing said sealing ring against said annular shoulder of the body member; a radially-deformable gripping ring having one end abuttable against said compression sleeve, and also having an inner surface producing a gripping action with respect to the pipe when the gripping ring is radially deformed; and a securing nut having threads mating with the threads on the body member and engageable with said gripping ring to move the gripping ring axially and to effect said sealing action via the compression sleeve and the sealing ring, and also compress the gripping ring radially to effect said gripping action of the pipe received in said bore; wherein the bore in the body member is formed with an annular rib at the end thereof opposite to that formed with said annular shoulder, and the end of the compression sleeve facing the sealing ring is formed with an external rib dimensioned to releasably retain the compression sleeve, and the sealing ring, within the body member bore during the preliminary assembly of the coupling.
 18. The coupling according to claim 17, wherein said pipe coupling further comprises an axially-extending limit between said gripping ring and said body member effective to cause the nut, when tightened; (a) in an initial stage, to move the gripping ring and the compression sleeve until said limit element prevents further axial movement of the gripping ring, and (b) in a final stage, to radially deform the gripping ring to produce said gripping action, and then to compress said sealing ring against said internal annular shoulder of the body member to produce said sealing action.
 19. The coupling according to claim 18, wherein said nut is formed with an internal annular shoulder engageable with the end of the compression sleeve facing the gripping ring, which annular shoulder engages said end of the compression sleeve to move the compression sleeve and the sealing ring axially in said final stage, compressing said sealing ring against said internal annular shoulder of the body member.
 20. The coupling according to claim 19, wherein said compression sleeve is formed with a radial flange at the end thereof facing the gripping ring, said limit element includes a plurality of fingers spaced circumferentially around said abutting end of the gripping ring and extending axially towards the body member; said radial flange on the compression sleeve is formed with a recess for accommodating each of said fingers of the gripping ring; and in said initial stage (a), one end of the sealing ring is also moved axially to partially compress the sealing ring, which sealing ring is further compressed to produce said sealing action during said final stage (b).
 21. The coupling according to claim 17, wherein said sealing ring is integrally formed on its outer surface with at least two annular ribs, one at each end.
 22. The coupling according to claim 21 wherein the end ribs of the sealing ring are of substantially circular cross-section, and the sealing ring includes a middle rib of substantially triangular cross-section. 